The present invention relates to the field of photography and, more specifically, to a self-processing film unit including a sheet-like photosensitive film component and an attached liquid applicator holding a substantially uniformly distributed supply of a low viscosity processing liquid that is to be applied to a given outer surface area of the film component, following exposure, to initiate film processing.
Most commercially available self-processing or self-developing film units employ a relatively high viscosity, jelly-like processing liquid which is dispensed from a pod, following film exposure, and is spread between a predetermined pair of layers in the film unit to initiate processing, e.g. a development and diffusion transfer process.
This type of process works best when the high viscosity fluid is spread in a controlled manner so as to have a substantially uniform thickness over the entire image-forming area. Therefore, self-developing photographic systems employing high viscosity fluids generally include an elaborate spread control system utilizing a variety of spread control components. For example, the film unit generally includes precisely dimensioned side rails along which the pressure-applying rollers travel to control the thickness of the liquid layer. The film holding cassette may include spread control members integrally formed thereon for controlling the shape of the liquid wave front as it is advanced between the film unit layers. Also, it is recognized that the pressure-applying rollers in the camera, along with roller mounts and bearings, must be manufactured to precise tolerances to achieve satisfactory spreading.
While these spread control components perform in a most satisfactory manner, they are inherently expensive to manufacture and assemble and substantially add to the cost of self-developing photographic systems.
Recognition of the undesirable high cost of precisely spreading a relatively high viscosity liquid processing composition has lead to many proposed alternative systems that are well known in the prior art.
Some of these alternative systems contemplate treating or wetting one outer surface of the exposed film component with a low viscosity (having a consistency similar to water) liquid processing composition and employ a wide variety of structures and mechanisms to deliver the liquid to the surface that is to be wetted. The low viscosity liquid tends to be self-spreading and is much easier to apply in a uniform manner than the high viscosity liquid thereby dispensing with the need for elaborate and costly spread control components.
Commonly assigned co-pending application, U.S. Ser. No. 436,189, filed on Oct. 22, 1982, which is incorporated by reference herein, discloses and claims a self-processing film unit comprising a sheet-like photosensitive film component and a low viscosity liquid applicator secured to one end portion thereof. Representative examples of other self-developing film units and processing systems that employ a low viscosity processing liquid cited therein include U.S. Pat. Nos. 2,543,181; 3,306,747; 3,179,517; 3,314,792; 3,345,165; 3,907,563; 3,069,266; 3,498,203; 3,152,515; and 4,310,620.
The film component disclosed in the above-noted co-pending application includes one or more photosensitive layers and has an outer surface with a given area thereof that is configured to be wetted with a low viscosity processing liquid, following exposure, to initiate processing of the photosensitive film component.
The liquid applicator is secured to the film component so as to extend outwardly beyond one end thereof and includes a liquid and air impervious sheet dimensioned for extension over the outer surface in covering relation to the given area. The applicator also includes means on one surface of the impervious sheet yieldably holding a substantially uniformly distributed supply of a low viscosity processing liquid sufficient to wet the given area. The liquid holding means may include, for example, an absorbent pad soaked with the low viscosity processing liquid. The applicator is initially provided on the film component in a folded over and releasably sealed configuration wherein the impervious sheet forms and liquid and air impervious enclosure about the liquid holding means. Following exposure of the film component, the applicator is moved to an unsealed extended configuration overlying the outer surface with the liquid holding means in liquid yielding contact with the given area to effect wetting thereof.
Commonly assigned co-pending application U.S. Ser. No. 436,078, filed on Oct. 22, 1982, discloses a processing apparatus configured for use with the above-described self-developing film unit.
The disclosed processing apparatus comprises means for supporting such a film unit; and means engageable with the folded applicator for unsealing the impervious sheet and moving it to its extended configuration to locate the liquid holding means in liquid yielding contact with the given area to effect wetting thereof.
In the illustrated embodiment, the apparatus includes a movable pick mechanism for engaging the folded applicator and urging opposed wall sections thereof apart to break releasable seals about the periphery of the applicator enclosure. The pick also moves the unsealed applicator rearwardly to a partially deployed position over the sheet-like film component. The pick then urges the film unit into the bite of the pair of pressure-applying rollers which serve to urge the liquid holding means into good contact with the given area of the outer surface of the film component.
The above-described film unit goes a long way toward the desired goal of substantially reducing the overall cost of a self-developing photographic system by employing a low viscosity processing liquid applicator, thereby eliminating the requirement for expensive precision spread control components in the film unit, cassette and camera pressure-applying roller system needed to process film units that utilize a high viscosity processing liquid. However, it is recognized that the liquid applicator disclosed in the above-noted co-pending application requires a somewhat mechanically complex and, therefore, relatively expensive processing apparatus to unseal the applicator structure and move it from its folded position to its extended position. More specifically, the liquid applicator is structured in such a way that it is difficult for the processing apparatus to grip the folded applicator and apply the necessary forces thereto for unsealing it and moving it to its extended position.
Therefore, it is an object of the present invention to provide a low-cost self-processing film unit that includes a low viscosity liquid applicator which may be easily manipulated to effect processing of the film unit.
It is another object of the invention to provide such a film unit having a liquid applicator structure which readily lends itself to film processing manipulation by a simply constructed processing apparatus.
Yet another object of the invention is to provide such a self-processing film unit that includes a releasably sealed folded liquid applicator enclosure which may be readily unsealed in response to applicator manipulation during processing operations.
Another object of the present invention is to provide such a self-processing film unit which, in response to initial manipulation by a processing apparatus, undergoes a structural recombination of certain of its component parts to facilitate further manipulation by the processing apparatus.
Still another object of the present invention is to provide such a self-processing film unit that is compatible with a processing apparatus having a simply constructed pick mechanism for advancing the film unit.
Other objects of the invention will, in part, be obvious and will, in part, appear hereinafter.